Full Idea
For a 'precisification' we take a trivalent interpretation and preserve the T and F values, and then assign all the third values in some way to either T or F.
Clarification
A 'trivalent' interpretation has T, F and a third value, such as 'undetermined'
Gist of Idea
A 'precisification' of a trivalent interpretation reduces it to a bivalent interpretation
Source
Theodore Sider (Logic for Philosophy [2010], 3.4.5)
Book Reference
Sider,Theodore: 'Logic for Philosophy' [OUP 2010], p.83
A Reaction
[my informal summary of Sider's formal definition]